Incandescent lamp



E. HENKEL ET AL Oct. 16, 1928.

INCANDESCENT LAMP Filed Nov. 8, 1927 h m m oeW o tH .t n s M e n r ma a hm h T. H b

Patented Oct. 16, 1928.

UNITED STATES PATENT .osr cs.

ERICH HENKEL, OF TBEPTOW, BERLIN, AND HANS WOLFE, 0F BERLIN, GERMANY, ASSIGNORS TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

INCANDESCEN'I' LAMP.

Application filed November 8, 1927, Serial No. 231,987, and in Germany December 7, 1926.

In the copending application of Wolff et al., Serial No. 66,642, filed November 3, 1925, there is disclosed a gas filled lamp with a lighting body which is entirely or for the greater art made of tungsten, the lamp containing sides the usual filling gases, such as neon or argon, which are chemically inert with respect to the incandescent body, hydrogen or gaseous or volatile halogen compounds;

It has been indicated in the prior application above noted that the additions made to the inert gas cause, besides other effects, a decrease in the danger of short circuits or undesirable electric discharges in the lamp. It is one of 'the objects of the resent invention to provide a gas filled lamp 111 which this danger is still further reduced.

In the operation of high candle power, gas filled incandescent lamps in which the lighting body is arranged in a narrow or restricted space as, for example, in projection lamps, the danger of short circuits is very great. We have found however that if such a lamp, containin the usual filling gases, is also provided efore being put into operation with a halogen ammonium salt, the danger of short circuits or undesirable electrical discharges is substantially prevented. The introduction of ammonium chloride and ammonium iodide into the lamp interior has been found to be specially advantageous for this purpose.

The novel features which we believe to be characteristic of our invention are set forth with particularity in the appended claims. The invention itself will best be understood from reference to the following specification when considered in connection with the accompanying drawing in which Fig. 1 is a cross sectional view partly broken away of a lamp embod ing the features of our invention; while ig. 2 is a plan view on an enlarged scale of the lamp coils andconnections thereto.

Referring more particularly to the drawing, we have indicated at 1 a receptacle havin a reentraht stem 2 provided with the usua press 3 and pump outlet 4. A capsule 5 filled with ammonium chloride or ammonium iodide and having a capillary opening 6 is placed in the pump outlet prior to the evacuation of the receptacle 1 and supported on resilient material 7, such as cotton or tungsten wool. After the receptacle has been'evacuated and filled to a definite pressure with inert gas thepump outlet is sealed off, as indi-' cated at 8. I

The filament comprises four coils 9 to 12 in elusive which are connected as indicated in Fig. 2 and supplied with current from the leading-in wires 13 and 14. The upper ends of the coils are supported from two wires 15 and 16 which are provided at their upper ends with hooks 17 and 18 respectively. Tensionis applied to the lower ends of the coils through a spring member 19 provided with a hook '20 which engages the connection between coils 10 and 11 at the point 21.

When placing the lamp into operation the vapor produced by the filament heat disassociates the halogen ammonium salt-into ammonia and a halogen compound of hydrogen, the former separating in a great measure mto free hydrogen and nitrogen. It is our opinion that in the chemical processes which take placethe free electrons issuing from the incandescent body are consumed relatively rapidly and therefore the formation of an electron current isinterferred with considerably so that gas ionization and short circuits cannot readily occur.

The halogen ammonium salt may be located at any part in the interior of the desirable, however, to provide for an extremeamp. It is' 1y slow delivery of the halogen vapor. This may be accomplished if the capsule 5 having a capillary opening 6 and containing the halogen ammonium salt is embedded in the pump outlet 4 which is fused to the bottom of the stem as indicated in Fig. 1. The salt in this case is heated just enough by the operation of the lamp to cause an extremely small vapor provided with a lighting body operable at incandescence, said receptacle containing a gaseous filling and in addition ammonium chloing a receptacle provided. with a tungsten 10 ride. lighting body and a gas filling consisting 3. An electric lamp comprising a receptacle largely of a gas chemically inert with respect provided with a lighting body Operable at into the tungsten, but containing a halogen acid 5 candescence, said receptacle having a gaseous gas, free nitrogen and free hydrogen.

filling, said filling including a gas chemically In Witness whereof, We have hereunto set 15 inert with respect to the lighting body, a haloour hands this 25th day of October, 1927. gen acid gas, iree nitrogen and free hydrogen. ERICH HENKEL.

4. An electric incandescent lamp compris- HANS WOLFF. 

